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devlian [24]
3 years ago
7

2. Peppered moths are typically either white with black speckles or black with white speckles. Before the Industrial Revolution,

the lighter moths were more prevalent. After the Industrial Revolution, the darker moths thrived in cities. This was because
Chemistry
1 answer:
Viktor [21]3 years ago
5 0
The pollution in the cities darkened basically everything, meaning the lighter colored moths were more visible, and were targeted. The dark ones, as a rule, lived whereas the light ones did not. This is an example of evolution.
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In the dark waters just below the photic zone, because of cellular respiration, the concentration of dissolved __________ is hig
Dafna1 [17]
In the dark waters just below the photic zone, because of cellular respiration, the concentration of dissolved carbon dioxide is higher relative to dissolved oxygen. 
In cellular respiration living organisms use oxygen and release carbon dioxide, because there is little or no light there is no photosynthesis and oxygen is little produced.
7 0
3 years ago
How many moles of aluminum are needed to react completely with 1.2 mol of feo
Amanda [17]

Answer:

0.8 mol.

Explanation:

  • The balanced equation for the reaction between Al and FeO is represented as:

<em>2Al + 3FeO → 3Fe + Al₂O₃,</em>

It is clear that 2 mol of Al react with 3 mol of FeO to produce 3 mol of Fe and 1 mol of Al₂O₃.

<em><u>Using cross multiplication:</u></em>

2 mol of Al needs → 3 mol of FeO, from stichiometry.

??? mol of Al needs → 1.2 mol of FeO.

∴<em> The no. of moles of Al are needed to react completely with 1.2 mol of FeO </em>= (2 mol)(1.2 mol)/(3 mol) = <em>0.8 mol.</em>

3 0
3 years ago
For the reaction: CH3NH2(aq) + H2O(aq) ⇌ CH3NH3 +(aq) + OH- Determine the change in the pH (ΔpH) for the addition of 6.7 M CH3NH
Korolek [52]

Answer:

The change in the pH (ΔpH) is 2,17

Explanation:

The reaction:

CH₃NH₂(aq) + H₂O(aq) ⇌ CH₃NH₃⁺(aq) + OH⁻

kb = \frac{[OH^{-}][CH_{3}NH_{3}^+]}{[CH_{3}NH_{2}]} <em>(1)</em>

In equilibrium, a solution of CH₃NH₂ 4,7M produces:

[CH₃NH₂] = 4,7 - x

[CH₃NH₃⁺] = x

[OH⁻] = x

Replacing in (1):

4,38x10^{-4} = \frac{x^2}{4,7-x}

x² + 4,38x10⁻⁴x - 2,0586x10⁻³ = 0

The solutions are:

x = -0,0456 No physical sense. There are not negative concentrations.

x = 0,04515 Real answer.

The concentration of [OH⁻] is 0,04515 M.

As pOH = -log [OH⁻] And pH+pOH = 14. The pH of this solution is:

<em>pH = 12,65</em>

The addition of 6,7M produce this changes in concentrations:

[CH₃NH₂] = 4,656 + x

[CH₃NH₃⁺] = 6,74515 - x

[OH⁻] = 0,04515 - x

Replacing in (1) you will obtain:

x² - 6,7907x + 0,3025 = 0

Solving for x:

x = 6,74586 No physical sense

x = 0,04484 Real answer.

Thus, [OH⁻] = 0,04515 - 0,044842 = 3,08x10⁻⁴M

pOH = 3,51.

<em>pH = 10,49</em>

Thus ΔpH is 12,65 - 10,49 = <em>2,16 ≈ 2,17</em>

I hope it helps!

4 0
3 years ago
What is meant by collision theory?
Tcecarenko [31]

Answer:

The collision theory states that a chemical reaction can only occur between particles when they collide (hit each other).

<em>h</em><em>o</em><em>p</em><em>e</em><em> </em><em>i</em><em>t</em><em> </em><em>h</em><em>e</em><em>l</em><em>p</em><em>s</em><em>~</em>

4 0
2 years ago
Where does the largest percent of water exist on Earth?
Ivanshal [37]

Answer:

97% of earth's water is in the ocean. The rest could be found underground, in glaciers and ice, and in rivers and lakes

3 0
3 years ago
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